package LeetCodeTest.PrimaryAlgorithmTest.Array;

public class IsValidSudoku {
    /**
     * 请你判断一个9x9 的数独是否有效。只需要 根据以下规则 ，验证已经填入的数字是否有效即可。
     *
     * 数字1-9在每一行只能出现一次。
     * 数字1-9在每一列只能出现一次。
     * 数字1-9在每一个以粗实线分隔的3x3宫内只能出现一次。（请参考示例图）
     * 数独部分空格内已填入了数字，空白格用'.'表示。
     * 注意：
     * 一个有效的数独（部分已被填充）不一定是可解的。
     * 只需要根据以上规则，验证已经填入的数字是否有效即可。
     * 示例 1：
     * 输入：board =
     * [["5","3",".",".","7",".",".",".","."]
     * ,["6",".",".","1","9","5",".",".","."]
     * ,[".","9","8",".",".",".",".","6","."]
     * ,["8",".",".",".","6",".",".",".","3"]
     * ,["4",".",".","8",".","3",".",".","1"]
     * ,["7",".",".",".","2",".",".",".","6"]
     * ,[".","6",".",".",".",".","2","8","."]
     * ,[".",".",".","4","1","9",".",".","5"]
     * ,[".",".",".",".","8",".",".","7","9"]]
     * 输出：true
     * 示例 2：
     * 输入：board =
     * [["8","3",".",".","7",".",".",".","."]
     * ,["6",".",".","1","9","5",".",".","."]
     * ,[".","9","8",".",".",".",".","6","."]
     * ,["8",".",".",".","6",".",".",".","3"]
     * ,["4",".",".","8",".","3",".",".","1"]
     * ,["7",".",".",".","2",".",".",".","6"]
     * ,[".","6",".",".",".",".","2","8","."]
     * ,[".",".",".","4","1","9",".",".","5"]
     * ,[".",".",".",".","8",".",".","7","9"]]
     * 输出：false
     * 解释：除了第一行的第一个数字从 5 改为 8 以外，空格内其他数字均与 示例1 相同。 但由于位于左上角的 3x3 宫内有两个 8 存在, 因此这个数独是无效的。
     *
     * 提示：
     *
     * board.length == 9
     * board[i].length == 9
     * board[i][j] 是一位数字或者 '.'
     *
     * 作者：力扣 (LeetCode)
     * 链接：https://leetcode-cn.com/leetbook/read/top-interview-questions-easy/x2f9gg/
     * 来源：力扣（LeetCode）
     * 著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
     *
     *
     */
    public static void main(String[] args) {
        String[][] board = {{"5","3",".",".","7",".",".",".","."}
,{"6",".",".","1","9","5",".",".","."}
,{".","9","8",".",".",".",".","6","."}
,{"8",".",".",".","6",".",".",".","3"}
,{"4",".",".","8",".","3",".",".","1"}
,{"7",".",".",".","2",".",".",".","6"}
,{".","6",".",".",".",".","2","8","."}
,{".",".",".","4","1","9",".",".","5"}
,{".",".",".",".","8",".",".","7","9"}};
    }

    public boolean isValidSudoku(char[][] board) {
        int[] line = new int[9];
        int[] column = new int[9];
        int[] cell = new int[9];
        int shift = 0;
        for (int i = 0; i < 9; i++) {
            for (int j = 0; j < 9; j++) {
                //如果还没有填数字，直接跳过
                if (board[i][j] == '.')
                    continue;
                shift = 1 << (board[i][j] - '0');
                int k = (i / 3) * 3 + j / 3;
                //如果对应的位置只要有一个大于0，说明有冲突，直接返回false
                if ((column[i] & shift) > 0 || (line[j] & shift) > 0 || (cell[k] & shift) > 0)
                    return false;
                column[i] |= shift;
                line[j] |= shift;
                cell[k] |= shift;
            }
        }
        return true;
    }
}
